Comparator gauge



Dec. 23; 1 969 E. CLARK 3,484,945

COMPARATOR GAUGE Filed July 24, 1967 ATTORNEYS.

United States Patent O 3,484,945 COMPARATOR GAUGE Arthur E. Clark, 745 LaPrairie, Ferndale, Mich. 48220 Filed July 24, 1967, Ser. No. 655,434 Int. Cl. G01]: /20; B43] 7/00 U.S. Cl. 33-201 9 Claims ABSTRACT OF THE DISCLOSURE A comparator gauge having a gauge head member that can be adjusted to an infinite number of positions by means of a cooperating releasable wedge lock means and a slotted base member.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to a comparator gauge of the type used in shop practice for use in checking tool angles and sizes, as for example a gauge for determining the angle of twist drill points, and which includes a positive locking means to clamp the gauge head in a set position on a slide member.

Description of the prior art tachments and additional operations for measuring various angles and lengths of the drill or other tools which is being measured.

SUMMARY According to the present invention, these difficulties are eliminated by the design of a sturdy and durable machinists gauge having a gauge head which will not slip when jarred or roughly handled and will always be maintained in accurate alignment with its base, thus insuring accurate measurement under the most difficult conditions. This is accomplished by providing a clamp screw with a wedge member which locks when the screw is turned down towards the member in the head in a slot provided in the slide member. As the screw is turned down to a tightened position, it acts on a leaf spring or cam member to wedge the bifurcated slide against the inner faces of the head to bring the bearing edges thereof into firm contact.

It is accordingly one of the objects of the invention to design a sturdy and durable gauge which includes a gauge head which will not slip when jarred or roughly handled, and will always be accurately aligned with its base.

Still another object of the invention is to provide a gauge so arranged as to .be placed for ready comparison with the cutting edges of the tool.

Another object of the invention is to provide a flexible means on the clamp screw to prevent binding after the gauge head has been approximately set.

A still further object of the invention is to design a machinists gauge of the type described which can be easily and economically manufactured and assembled, and which can be readily disassembled when necessary for repair or replacement or broken or worn parts.

Other objects and advantages of this invention will become apparent during the course of the following description:

3,484,945 Patented Dec. 23, 1969 FIG. 1 is a perspective View of the gauge assembly of the present invention;

FIG. 2 is a vertical, transverse sectional view to an enlarged scale of the gauge taken on the line 2-2 of FIG. 1;

FIG. 3 is a modified form of the clamping device as shown in the cross-sectional view of FIG. 2;

FIG. 4 is a fragmentary side View of the gauge with a drill in position showing one application of the gauge of the present invention;

FIG. 5 is a fragmentary perspective view of a modified base member for use with the slidable head.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 which illustrates a preferred embodiment, a gauge designated by the numeral 10 having head 12, a slide 14 and a knurled thumb screw 16 for clamping the head to the slide in any desired position of adjustment. The head 12 is provided with blades 18 and 20 which are securely attached as by welding to the flanges 22 and 24 of the channel 26.

The head 12 is slidable along the length of slot 28 to position the marginal edges of the: blades at their various angles with respect to longitudinal portions of the sides of slide 14. The slot 28 is formed centrally of the slide 14 throughout most of its length for the reception of the shank 30 extending from the thumb screw 16 and into a threaded aperture 32 formed in the base of the channel 26. The scale markings are provided on the slide 14 and extend along its longitudinal side edges. A cylindrical shoulder 34 is provided on the thumb screw 16 to how a flexible leaf spring 36 mounted between the screw 30 and the slide 14 into the slot 28.

The spring 36 is of such size as to extend on either side of slot 28 whereby the upper edges of the slot 28 constitute fulcrums bearing against the under portion of the spring whereby the leaf spring spreads the sides of the slide against the inner edges 44 and 46 of the blades to bring them into firm contact with the side edges 48 and 50 of the slide upon tightening of the thumb screw 16.

In FIG. 3 a modification is shown on which the only differences from FIG. 2 is that a wedge member 52 is used in place of the leaf spring 36 in the embodiment of FIG. 2. The mode of operation for applicants device remains the same, however, wherein the thumb screw 16 is turned down to hold head 12 in position. It can be seen that in either form of the invention the screw 16 need only be slightly turned to accomplish sufiicient binding between the edges 44, 48 and 46, 50 to prevent movement of head 12, and to set the head 12 always in accurate alignment with respect to the slide 14.

The advantage of the invention, whether in. the form of FIG. 2 or FIG. 3, is the attainment of a line contact with the upper slot edges by member 36 or 52 to thereby prevent undue wear and marking of the edges even after repeated use. The line contact arrangement also provides binding of the edges 44, 48 and 46, 50 to insure a uniform alignment of the head 12 with the base 14 at each new position of the head.

It should be noted that applicant's invention contemplates that the slide 14 have sufficient thickness to provide a rigid member wherein the slide edges 48 and 50 provide sufficient bearing contact surfaces for accurately holding the tool to be measured so that its axis is aligned with the axis of the base scale. In the embodiment shown the slide 14 has a thickness of the order of one-eighth inch to provide this contact surface.

In practice, the gauge head is set quickly by loosening the thumbscrew 16 and moving the head to a position where the twist drill 58 can be held against edge 50 of slide 14 and the thumbscrew tightened as shown in FIG. 4. As some drills are provided with shanks 54 of greater diameter than their bodies such as square or tapered shank drills, for example, and indicated by the dashed lines 60, applicants gauge allows the full body of the drill to be aligned in contact with edge 50 of the slide. It will be noted that blade 20 has its edge 62 sloped at an angle of 59 for checking the point 56 of the drill 58. The 59 angle is, of course, standard for most drill applications and allows for quick comparison to see if the drill has been correctly ground. The other edges of the blade 20 are sloped at other angles for checking the angles of other types of drills or cutting tools.

The head 12 can be positioned at either end of the slot 28 to provide a suflicient side edge on the slide 14 against which the shank of the tool will lie. Scales 63 are preferably inscribed along both sides of the slide 14 20 for checking tool lengths. Scale 65 inscribed on the edges of the blades 18 and 20 are used to check the dimensions of the two drill cutting edges to insure uniformity and accuracy.

An alternative form of base scale is shown in FIG. wherein the base 64 is provided with a series of threaded holes 66 to allow the head 12 to be positioned at various fixed locations along the base.

Although I have described the preferred embodiments of my invention, it will be understood that many modifications and revisions may be made therein without departing from the spirit of the invention.

What is claimed is:

1. A gauge, comprising:

(a) a head having a pair of spaced, opposed sides, and a straight marginal edge meeting at least one of the opposed sides;

(b) an elongated slide having a straight, longitudinal side edge and a longitudinal slot parallel to said straight side edge, the slide being receivable between the opposed sides of the head in a position in which the straight side edge is adjacent the straight marginal edge; and

(0) means for fastening the head and the slide together including means for laterally spreading the longitudinal sides of the slide into engagement with the opposed sides of the head whereby the straight side edge of the slide and the straight marginal edge of the head meet one another to form a reference angle for comparison with the angular profile of a tool.

2. The combination as defined in claim 1, in which the last mentioned means comprises a retainer releasably engagable with the slide to allow the head to be fastened at a selected longitudinal position along the slide.

3. The combination as defined in claim 1, including indicia inscribed on the head along its straight marginal edge.

4. The combination as defined in claim 1, in which said last mentioned means comprises a leaf spring retainer for biasing opposite sides of the slot away from one another.

5. A combination as defined in claim 1, in which said last mentioned means comprises a wedge retainer for spreading opposite sides of the slot away from one another.

6. The combination as defined in claim 1, in which the head has a second straight marginal edge meeting one of said opposed sides, and the slide has a straight longitudinal edge for meeting the second straight marginal edge to form a second reference angle.

7. The combination as defiined in claim 6, in which the two straight marginal edges of the head meet opposite one of the opposed sides.

8. The combination as defined in claim 6, in which the two straight marginal edges of the head meet the same opposed side.

9. A guage having a reference angle for comparison with the contour of a twist drill point, comprising:

(a) a head having a pair of planar blades fixed with respect to one another, each blade having a straight edge opposing and parallel to a similar straight edge of the other blade, at least one straight marginal edge meeting said blade straight edge in a predetermined angle to form a corner, and indicia formed along said straight marginal edge;

(b) an elongated slide having a longitudinal slot formed between a pair of straight longitudinal sides, the slide being received between the opposing blade straight edges in a position in which each straight longitudinal side is adjacent a corner of the head; and

(c) a fastener connecting the head and the slide to releasably lock them together, and means on said fastener spreading the straight longitudinal sides of the slide into contact with the opposing blade straight edges such that each straight longitudinal side meets a straight marginal edge to form a predetermined reference angle at their juncture for comparison with the angle between the cutting edge and the shank of a twist drill.

References Cited UNITED STATES PATENTS 135,809 2/1873 Hubbard 151-38 278,678 6/1883 Blighton 151-38 X 283,907 8/1883 Low 33-150 2,597,300 5/1952 Cuff 33-201 2,638,678 5/1953 Darabaris. 3,089,245 5/1963 Cromer et al. 3,273,246 9/1966 Siberini 33-103 3,293,752 12/1966 Shuman 33-103 X 5 WILLIAM D. MARTIN, JR., Primary Examiner US Cl. X.R. 33-103 

